The present invention relates to a zoom lens barrel unit of a zoom lens camera or other similar device and a viewfinder of a zoom lens camera. More specifically, the present invention relates to a zoom lens barrel unit which is more compact in the retracted position and a viewfinder of a zoom lens camera in which a zoom lens barrel unit is made more compact through the provision of a smaller cam ring for detecting the degree of zooming.
One example of a conventional zoom lens of the prior art is disclosed in Japanese Patent Publication Laid-Open No. 306808/1989. The structure and operation of that conventional zoom lens is bulky both in length and diameter than is desired. This result exists because the inside of the barrel unit in this disclosure has cam grooves required for operation. Also, a moving mechanism is made of several pieces, at least one of which that is required for zoom operation.
A further conventional zoom lens camera which conducts a zooming operation interlockingly with the zooming of a photographic optical system is described, for example, in Japanese Patent Publication Laid-Open No. 207731/1989. A viewfinder of such a conventional zoom lens camera sits on the cam in the barrel so that the viewfinder will move with the cam. This requires that the cam groove be extended to have a length corresponding to the maximum axial movement of the viewfinder. This requires a longer barrel member than is desired.
The present invention seeks to remedy these drawbacks of the prior art, allowing for the manufacture of a zoom lens which is more compact in the retracted position and a viewfinder of a zoom lens camera in which the zoom lens barrel unit is made more compact through the provision of a smaller cam ring used for detecting the degree of zooming.